Message Peeping Tom lets you reply to messages when you want without leaving friends hanging
Unlike them, it doesn't give the other side a clue that you've read their musings, so the dreaded "Seen... 2 days ago" message is dealt with for good. Right now, MPT supports Line, Facebook Messenger, Kakao Talk, Hike, Between, and China's Momo. Obviously, this app was made with the Asian market in mind, but the English translation it has will suffice.
The app is still being worked on, so it might exhibit a bug or two as you go about using it. But as it grows more popular, the kinks will be ironed out and more people will start enjoying their rightful privilege of replying messages whenever they darn please.
Download Message Peeping Tom: Android
via Tech In Asia